Add a comment on StringRef::contains(char)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282350 91177308-0d34-0410-b5e6-96231b3b80d8

Author: Zachary Turner

include/llvm/ADT/StringRef.h

@@ -379,6 +379,8 @@ namespace llvm {
     LLVM_ATTRIBUTE_ALWAYS_INLINE
     bool contains(StringRef Other) const { return find(Other) != npos; }
 
+    /// Return true if the given character is contained in *this, and false
+    /// otherwise.
     LLVM_ATTRIBUTE_ALWAYS_INLINE
     bool contains(char C) const { return find_first_of(C) != npos; }